There are very few ants that will actually damage plants. Ants will, however, farm aphids just like we herd cattle. The aphids do the damage. Ever seen a rose bud destroyed by aphids? Aphids create a substance called honeydew which the ants feed on. The honeydew also supports the growth of a black mold. Is there any present? If so, this could indicate that you really have an aphid problem.

Ants can be kept off plants by banding the plant with cotton batting painted with a sticky substance called tanglefoot but this would be hard to do with a zucchini plant. It is also said that ants will back away from lines of bone meal (available at you local garden center).

It is also possible that the ants are the obvious but another critter is the culprit. Got any slugs, snails, or ? in your area?